Diabetes is widely recognized as a major health concern among African Americans and Hispanics in the U.S. Relatively little attention has been directed to childhood diabetes as a component of this problem, however. Although the risk of insulin-dependent diabetes mellitus (IDDM) is generally thought to be lower among minority children and adolescents than among non-Hispanic whites, there is evidence that the associated morbidity and mortality may well be increased. Type I diabetes is an important disease of childhood due to its relative prevalence, the costs of lifelong treatment, and the long term risks for complications and premature mortality. The knowledge base regarding the descriptive epidemiology of IDDM among blacks and urban Hispanics in the United States remains very weak, in large measure because there have been no attempts to organize studies on multiple risk factors in a population center of sufficient size. Therefore we propose a population-based registry of black and Latino childhood diabetes patients in Chicago. The Chicago metropolitan area is home to large numbers of African-Americans and Hispanics, as well as other immigrant groups, and provides a unique opportunity to study the patterns of diabetes incidence in these minority populations. It is only with basic incidence data in hand that attempts to delay or prevent complications among minority children and to address the social costs of the disease, will become feasible. The data from this registry will allow the evaluation of differences in risk for IDDM in blacks and Hispanics. Specifically, the proposed research will: 1) determine the incidence of IDDM retrospectively from 1985 to 1990, and prospectively to 1995, in black and Hispanic children under the age of 18 in the city of Chicago, Illinois; 2) examine incidence within ethnic groups by socioeconomic status; 3) determine if the incidence of IDDM varies by sex, by age, or by the season of the year, and whether the incidence rate has increased, decreased, or has remained stable over the study period; and 4) determine whether the incidence of IDDM among Hispanic populations varies with geographic location of origin and with the degree of genetic admixture present. Once the registry population is established, further studies will assess the natural history of the disease and evaluate the quality of care for minority populations. Specific research questions will address certain genetic associations with IDDM in minority patients, patterns of familial aggregation of IDDM and the social and financial impact of the disease on minority families.